The state-of-the-art is indicated by the following cited references: Gottschalk, U.S. Pat. Nos. 5,495,738; Gottschalk, et al., 5,445,003; Bone, 5,493,761; Winkens, 5,138,859; Berstein, 4,561,276; and Ostertag, 4,947,668.
Various machines and methods have been employed to strengthen and finish metal workpieces such as the camshafts and crankshafts for internal combustion engines. In many modern automobiles, engines have been downsized for installation into smaller vehicles. Accordingly, with downsizing of automotive vehicles and their components for reducing weights and improving fuel efficiency, smaller engines and crankshafts are needed. To improve the fatigue strength and durability of downsized crankshafts, deep rolling of fillets and other circular joint areas is increasingly important. Fatigue strength and durability of crank pins and main bearing journals can be significantly increased by deep rolling compressive stresses into the metal of the annular fillets between the pin journals and the adjacent counter weights or balancing webs.
In connection with the process for manufacturing the upper work rollers used in the deep rolling of crankshafts, such work rollers are expensive to produce and the response time to fill an order for such work rollers is quite lengthy. Accordingly, those skilled in the art have long sought an economical and efficient way to produce such work rollers. In the past, there have occurred particular problems in the area of advantageously, economically, and promptly producing such work rollers.
One object of this invention is to provide a novel process for manufacturing work rollers which is economical, and can be carried out promptly and expeditiously from a time saving viewpoint.
Another object of the present invention is to provide a novel process for manufacturing work rollers that is of such versatility to advantageously shorten the response time to an order.
Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in connection with the accompanying drawings (wherein like numerals indicate like elements).